1. Field of the Invention
The present invention relates to an apparatus which can record information on and reproduce information from a recordable and reproducible disc, and more particularly, to a method of verifying that a disc recording and reproducing apparatus normally generates or updates defect management area (DMA) information of a disc, and a test apparatus for performing the same.
2. Description of the Related Art
A recordable and reproducible disc is an optical disc, which information is recorded on and reproduced from using a laser, for example, a digital versatile disc random access memory (DVD-RAM). A DVD-RAM is a rewritable disc. According to “DVD Specifications for Rewritable Disc Part 1 Physical Specifications Version 2.0,” a DVD-RAM includes four DMAs, i.e., DMA1, DMA2, DMA3 and DMA4, on each side thereof for managing the defects thereon.
As shown in FIG. 1, DMA1 and DMA2 are located in a lead-in area near the inner diameter of a disc, and DMA3 and DMA4 are located in a lead-out area near the outer diameter of the disc. Each DMA is followed by a reserved sector.
A disc definition structure (DDS), a primary defect list (PDL) and a secondary defect list (SDL) are stored in the DMA. A DDS includes information on the format structure of a disc, for example, a disc certification flag, a DDS/PDL update counter and a start logical sector number of each zone. A PDL includes information on all defective sectors detected on the disc during initialization of the disc. An SDL includes information on the sector number of each first sector in defective blocks (error-correction code (ECC) blocks) occurring while the disc is in use, information on the sector number of each first sector in spare blocks which are used to replace defective blocks and information on a spare area.
Some information included in the DMA can be immediately read and used. On the other hand, the DMA includes information which varies with the positions and the number of defects on a disc. In addition, some information, for example, the position information of the start sector number of each zone or the position information of a logical sector number 0, can be obtained by performing an algorithm based on defect information registered in the DMA.
Four DMAs exist on each side of a disc to prevent erroneous defect management due to errors in the DMA information. Since such DMA information is closely related to a physical data sector, a recording medium such as a movable optical disc may not be compatible with two different disc recording and reproducing apparatuses when the DMA information is incorrectly written or read.
This is because, when the recording and reproducing architecture of a disc recording and reproducing apparatus (for example, a DVD-RAM recording and reproducing apparatus) is divided into a file system layer, a host interface layer for interfacing a host computer with the recording and reproducing apparatus, a physical disc recording and reproducing apparatus (or a disc drive unit) layer for recording and reproducing physical signals, and a recording medium layer, writing and reading of DMA information is performed in the physical disc recording and reproducing apparatus layer and the layers therebelow.
In an actual file system, user information to be recorded or reproduced is transmitted to a disc recording and reproducing apparatus based on only a logical sector number, and the disc recording and reproducing apparatus converts the logical sector number into a physical sector number to record or reproduce the user information. In this case, DMA information is used. Accordingly, when the DMA information has erroneously been read or written in a given disc recording and reproducing apparatus, data cannot be correctly read or written in another recording and reproducing apparatus.
Accordingly, a method of verifying that a disc recording and reproducing apparatus correctly reads DMA information recorded on a disc and correctly records DMA information on the disc for generation or update of DMA information is desired.